1. Field of the Invention
The present invention relates to a mounting assembly for wave-shaped metal roof plates, and more particularly to such a roof plate mounting assembly capable of effectively preventing roof plates from being distorted or being broken at their clamping holes due to their longitudinal expansion and shrinkage.
2. Description of the Prior Art
For mounting wave-shaped metal roof plates, C-beams are conventionally used. On each C-beam, a tight frame is fixedly mounted. A roof plate support member is arranged on the tight frame in the same direction as the C-beam. On the roof plate support member, one connecting edge portion, namely, the leading connecting edge portion of a roof plate is laid. The other connecting edge portion, namely, the trailing connecting edge portion of the roof plate is laid on the leading connecting edge portion of another roof plate laid on another roof plate support member to be connected with the former roof plate. To each roof plate support member, overlapping connecting edge portions of the roof plates to be connected to each other are fixedly mounted by means of bolts or set screws. In order to prevent rainwater from coming through the clamping holes formed for fixedly mounting the roof plates to each roof plate support member, those clamping holes are sealed with a waterproof liquid, waterproof paint or sealant.
Such wave-shaped metal roof plates mounted in the above-mentioned manner are subjected to variations in the temperature of the atmosphere, thereby being longitudinally and laterally expanded or shrunk. Although the lateral expansion and shrinkage of such metal roof plates do not result in unfavorable effect is on the metal roof plates, the longitudinal expansion and shrinkage are problematic because there is no means for coping therewith. Due to the longitudinal expansion and shrinkage of the roof plates, for example, bolt or screw holes formed at the roof plates may be torn. Otherwise, the roof plates may be distorted at their portions around the bolt or screw holes. This is because each roof plate support member is fixed to each tight frame, thereby disabling the associated roof plates to cope with the longitudinal expansion and shrinkage thereof.
Typically, such metal roof plates have trapezoidal corrugations each having a flat top surface. Each connecting edge portion of each roof plate is also flat because it is provided by cutting a required corrugation at its flat top surface. In practical cases, roof plates often have non-linear flat surfaces at their connecting edge portions due to their partial distortion.
Where such roof plates having incompletely flat connecting edge portions are connected to each other, it is difficult to expect a perfect contact, as in two glass sheets being overlapped, between overlapping connecting edge portions thereof throughout the length thereof. In other words, the roof plates have non-contact areas along their overlapping connecting edge portions. In this case, there is a fatal problem in the durability of roof plates because rainwater may come through the non-contact areas, thereby causing the roof plates to rust on their inner surfaces.